I don’t know about the IF as this was a zwift workouts. I’ll also add that in the 8 weeks of workouts, I completed all workouts successfully at higher FTP.
You are right about the 20 minutes! Normally, I have something to compare because I was doing some racing on zwift and trying my best 20mins. This year I havent done any race… But would definetely take a look at the other testing procedure to validate! thanks!